OpenVPN Web GUI & HTTP Issue resolution
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I've had issues with loading HTTP pages serviced by devices on my LAN, including the pfSense Webconfigurator
I see a number of posts about similar issues, but didn't see a solution. After many rabbit holes, I think I found a solution.
In your OpenVPN server config > Advanced Configuration > Custom Options, add:
tun-mtu 1450; mssfix 1410;Note that you may need to adjust the numbers in the above until your config works. I am not sure if the mssfix is needed. Once I did this, pages started loading. Interestingly, I removed these settings & pages still load. This may just be a temporary situation; I expect I'll need to the above back.
I did not get this far, but I believe the following command could be used in TMux on Android to test for the OpenVPN MTU setting above, the command is:
ping -s 1472 -c 3 -M do <ip of your lan device serving page>Adjust 1472 up or down 'til not packet loss, then add 28 to that number & put into your interface MTU should hopefully work.
Based on this site:
https://www.thegeekpub.com/271035/openvpn-mtu-finding-the-correct-settings/The following command can be used in the pfSense command line to test the MTU values for the interface. Adjust 1472 up or down 'til not packet loss, then add 28 to that number & put into your interface MTU.
ping -D -t 2 -c 3 -s 1472 8.8.8.8